<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>
		<style type="text/css">
			.p1 {
				width: 100px;
				background-color: burlywood;
				font-size: 20px;
				margin: 0 auto;
			}
			
			.p1:hover {
				/*监听鼠标滑动*/
				border-bottom: 2px solid blue;
			}
			
			a {
				width: 100px;
				height: 100px;
				background-color: blue;
				/*span,a 如果要占位置，需要设置成块元素*/
				display: inline-block;
				/*a标签去掉下划线*/
				text-decoration: none;
				
			}
		</style>
	</head>

	<body>
		<p class="p1">鼠标滑动</p>

		<a>123</a>

	</body>

</html>